The narrow two-dimensional topological insulator is characterized by the interedge backscattering originating from interedge coupling,which could greatly enrich topological superconducting electronics. Here,considering the interedge coupling,we apply Bogoliubov-de Gennes(BdG)equation to study the Josephson junction composed of a narrow two-dimen-sional topological insulator strip,where two superconducting electrodes at a distance of d are placed on the same edge of the strip. It is found that varying d could give rise to a 0-π state transition,which in turn can manifest the helical spin texture of the edge states. The mechanism stems from an additional π phase shift caused by the interedge backscattering,being different from the conventional one induced by the length of the ferromagnet sandwiched between two superconducting elec-trodes. Moreover,an unusually large residual value of the Josephson critical current at the 0-π state transition point is always exhibited.As a result,the results have potential applications in the designs of superconducting electronic devices,for instance,a supercurrent switch with a very efficient performance.